Some composite bodies, such as some composite parts used in the aerospace industry, may be manufactured from porous preforms. The porous preforms may be densified using one of several processes, for example, chemical vapor deposition/chemical vapor infiltration (CVD/CVI), vacuum pressure infiltration (VPI), high pressure impregnation/carbonization (PIC), or resin transfer molding (RTM), which may introduce carbon into the porous preform.